// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_BROWSER_BROWSER_CHILD_PROCESS_HOST_IMPL_H_
#define CONTENT_BROWSER_BROWSER_CHILD_PROCESS_HOST_IMPL_H_

#include <stdint.h>

#include <list>
#include <memory>

#include "base/compiler_specific.h"
#include "base/memory/ref_counted.h"
#include "base/memory/shared_memory.h"
#include "base/memory/weak_ptr.h"
#include "base/process/process.h"
#include "base/single_thread_task_runner.h"
#include "base/synchronization/waitable_event_watcher.h"
#include "build/build_config.h"
#include "content/browser/child_process_launcher.h"
#include "content/public/browser/browser_child_process_host.h"
#include "content/public/browser/child_process_data.h"
#include "content/public/common/child_process_host_delegate.h"

#if defined(OS_WIN)
#include "base/win/object_watcher.h"
#endif

namespace base {
class CommandLine;
}

namespace service_manager {
class InterfaceProvider;
}

namespace content {

class BrowserChildProcessHostIterator;
class BrowserChildProcessObserver;
class BrowserMessageFilter;
class ChildConnection;

// Plugins/workers and other child processes that live on the IO thread use this
// class. RenderProcessHostImpl is the main exception that doesn't use this
/// class because it lives on the UI thread.
class CONTENT_EXPORT BrowserChildProcessHostImpl
    : public BrowserChildProcessHost,
      public NON_EXPORTED_BASE(ChildProcessHostDelegate),
#if defined(OS_WIN)
      public base::win::ObjectWatcher::Delegate,
#endif
      public ChildProcessLauncher::Client {
public:
    BrowserChildProcessHostImpl(content::ProcessType process_type,
        BrowserChildProcessHostDelegate* delegate,
        const std::string& service_name);
    ~BrowserChildProcessHostImpl() override;

    // Terminates all child processes and deletes each BrowserChildProcessHost
    // instance.
    static void TerminateAll();

    // Copies kEnableFeatures and kDisableFeatures to the command line. Generates
    // them from the FeatureList override state, to take into account overrides
    // from FieldTrials.
    static void CopyFeatureAndFieldTrialFlags(base::CommandLine* cmd_line);

    // BrowserChildProcessHost implementation:
    bool Send(IPC::Message* message) override;
    void Launch(std::unique_ptr<SandboxedProcessLauncherDelegate> delegate,
        std::unique_ptr<base::CommandLine> cmd_line,
        bool terminate_on_shutdown) override;
    const ChildProcessData& GetData() const override;
    ChildProcessHost* GetHost() const override;
    base::TerminationStatus GetTerminationStatus(bool known_dead,
        int* exit_code) override;
    std::unique_ptr<base::SharedPersistentMemoryAllocator> TakeMetricsAllocator()
        override;
    void SetName(const base::string16& name) override;
    void SetHandle(base::ProcessHandle handle) override;
    std::string GetServiceRequestChannelToken() override;

    // ChildProcessHostDelegate implementation:
    bool CanShutdown() override;
    void OnChannelInitialized(IPC::Channel* channel) override;
    void OnChildDisconnected() override;
    const base::Process& GetProcess() const override;
    service_manager::InterfaceProvider* GetRemoteInterfaces() override;
    bool OnMessageReceived(const IPC::Message& message) override;
    void OnChannelConnected(int32_t peer_pid) override;
    void OnChannelError() override;
    void OnBadMessageReceived(const IPC::Message& message) override;

    // Terminates the process and logs a stack trace after a bad message was
    // received from the child process.
    void TerminateOnBadMessageReceived(const std::string& error);

    // Removes this host from the host list. Calls ChildProcessHost::ForceShutdown
    void ForceShutdown();

    // Callers can reduce the BrowserChildProcess' priority.
    void SetBackgrounded(bool backgrounded);

    // Adds an IPC message filter.
    void AddFilter(BrowserMessageFilter* filter);

    static void HistogramBadMessageTerminated(int process_type);

    BrowserChildProcessHostDelegate* delegate() const { return delegate_; }

    ChildConnection* child_connection() const
    {
        return child_connection_.get();
    }

    IPC::Channel* child_channel() const { return channel_; }

    typedef std::list<BrowserChildProcessHostImpl*> BrowserChildProcessList;

private:
    friend class BrowserChildProcessHostIterator;
    friend class BrowserChildProcessObserver;

    static BrowserChildProcessList* GetIterator();

    static void AddObserver(BrowserChildProcessObserver* observer);
    static void RemoveObserver(BrowserChildProcessObserver* observer);

    // Creates the |metrics_allocator_|.
    void CreateMetricsAllocator();

    // Passes the |metrics_allocator_|, if any, to the managed process. This
    // requires the process to have been launched and the IPC channel to be
    // available.
    void ShareMetricsAllocatorToProcess();

    // ChildProcessLauncher::Client implementation.
    void OnProcessLaunched() override;
    void OnProcessLaunchFailed(int error_code) override;

    // Returns true if the process has successfully launched. Must only be called
    // on the IO thread.
    bool IsProcessLaunched() const;

    static void OnMojoError(
        base::WeakPtr<BrowserChildProcessHostImpl> process,
        scoped_refptr<base::SingleThreadTaskRunner> task_runner,
        const std::string& error);

#if defined(OS_WIN)
    // ObjectWatcher::Delegate implementation.
    void OnObjectSignaled(HANDLE object) override;
#endif

    ChildProcessData data_;
    BrowserChildProcessHostDelegate* delegate_;
    std::unique_ptr<ChildProcessHost> child_process_host_;

    const std::string child_token_;
    std::unique_ptr<ChildConnection> child_connection_;

    std::unique_ptr<ChildProcessLauncher> child_process_;

#if defined(OS_WIN)
    // Watches to see if the child process exits before the IPC channel has
    // been connected. Thereafter, its exit is determined by an error on the
    // IPC channel.
    base::win::ObjectWatcher early_exit_watcher_;
#endif

    // The memory allocator, if any, in which the process will write its metrics.
    std::unique_ptr<base::SharedPersistentMemoryAllocator> metrics_allocator_;

    IPC::Channel* channel_ = nullptr;
    bool is_channel_connected_;
    bool notify_child_disconnected_;

    base::WeakPtrFactory<BrowserChildProcessHostImpl> weak_factory_;
};

} // namespace content

#endif // CONTENT_BROWSER_BROWSER_CHILD_PROCESS_HOST_IMPL_H_
